Channel and body region formation for semiconductor devices

ABSTRACT

Systems, methods and apparatus are provided for forming layers of a first dielectric material, a semiconductor material, and a second dielectric material in repeating iterations vertically to form a vertical stack and forming a vertical opening using an etchant process to expose vertical sidewalls in the vertical stack. A seed material that is selective to the semiconductor material is deposited over the vertical stack and the vertical sidewalls in the vertical stack and the seed material is processed such that the seed material advances within the semiconductor material such that it transforms a crystalline structure of a portion of the semiconductor material.

TECHNICAL FIELD

The present disclosure relates generally to memory devices, and moreparticularly, to channel and body region formation for semiconductordevices.

BACKGROUND

Memory is often implemented in electronic systems, such as computers,cell phones, hand-held devices, etc. There are many different types ofmemory, including volatile and non-volatile memory. Volatile memory mayrequire power to maintain its data and may include random-access memory(RAM), dynamic random-access memory (DRAM), static random-access memory(SRAM), and synchronous dynamic random-access memory (SDRAM).Non-volatile memory may provide persistent data by retaining stored datawhen not powered and may include NAND flash memory, NOR flash memory,nitride read only memory (NROM), phase-change memory (e.g., phase-changerandom access memory), resistive memory (e.g., resistive random-accessmemory), cross-point memory, ferroelectric random-access memory (FeRAM),or the like.

As design rules shrink, less semiconductor space is available tofabricate memory, including DRAM arrays. A respective memory cell forDRAM may include an access device, e.g., transistor, having a first anda second source/drain regions separated by a channel and body region. Agate may oppose the channel region and be separated therefrom by a gatedielectric. An access line, such as a word line, is electricallyconnected to the gate of the DRAM cell. A DRAM cell can include astorage node, such as a capacitor cell, coupled by the access device toa digit line. The access device can be activated (e.g., to select thecell) by an access line coupled to the access transistor. The capacitorcan store a charge corresponding to a data value of a respective cell(e.g., a logic “1” or “0”).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a vertical three dimensional (3D)memory in accordance a number of embodiments of the present disclosure.

FIG. 2 is a perspective view illustrating a channel and body region of athree-node access device for semiconductor devices in accordance with anumber of embodiments of the present disclosure.

FIG. 3 is a perspective view illustrating a channel and body region of athree-node access device for semiconductor devices in accordance with anumber of embodiments of the present disclosure.

FIGS. 4A-4F are cross-sectional views for forming arrays of verticallystacked memory cells, at multiple stages of a semiconductor fabricationprocess, to form a channel and body region for semiconductor devices, inaccordance with a number of embodiments of the present disclosure.

FIGS. 5A-5B illustrate an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices and vertically oriented access lines, in accordance with anumber of embodiments of the present disclosure.

FIGS. 6A to 6E illustrate an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure.

FIGS. 7A to 7E illustrate an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure.

FIGS. 8A to 8E illustrate an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure.

FIG. 9 is a block diagram of an apparatus in the form of a computingsystem including a memory device in accordance with a number ofembodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure describe channel and body regionformation for semiconductor devices. A channel and body region is formedwith horizontal access devices in an array of vertically stacked memorycells. The horizontal access devices are integrated with verticallyoriented access lines and integrated with horizontally oriented digitlines. The channel may provide improved electron mobility due to theincreased grain size of the amorphous silicon material in the channeland a decreased density in the grain boundary. The decreased grainboundary density may also decrease the electron hole pair generation anddecrease the value if the off current (Ioff). Further, the metal inducedlateral crystallization (MILC) distance may be such that it only coversthe channel region. This may decrease the anneal process time incomparison to other processes not disclosed herein.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the figure number of the drawing and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, reference numeral104 may reference element “04” in FIG. 1, and a similar element may bereferenced as 204 in FIG. 2. Multiple analogous elements within onefigure may be referenced with a reference numeral followed by a hyphenand another numeral or a letter. For example, 302-1 may referenceelement 302-1 in FIG. 3 and 302-2 may reference element 302-2, which maybe analogous to element 302-1. Such analogous elements may be generallyreferenced without the hyphen and extra numeral or letter. For example,elements 302-1 and 302-2 or other analogous elements may be generallyreferenced as 302.

FIG. 1 is a block diagram of an apparatus in accordance a number ofembodiments of the present disclosure. FIG. 1 illustrates a circuitdiagram showing a cell array of a three dimensional (3D) semiconductormemory device according to embodiments of the present disclosure. FIG. 1illustrates a cell array may have a plurality of sub cell arrays 101-1,101-2, . . . , 101-N. The sub cell arrays 101-1, 101-2, . . . , 101-Nmay be arranged along a second direction (D2) 105. Each of the sub cellarrays, e.g., sub cell array 101-2, may include a plurality of accesslines 103-1, 103-2, . . . , 103-Q (which also may be referred to a wordlines). Also, each of the sub cell arrays, e.g., sub cell array 101-2,may include a plurality of digit lines 107-1, 107-2, . . . , 107-P(which also may be referred to as bit lines, data lines, or senselines). In FIG. 1, the digit lines 107-1, 107-2, . . . , 107-P areillustrated extending in a first direction (D1) 109 and the access lines103-1, 103-2, . . . , 103-Q are illustrated extending in a thirddirection (D3) 111. According to embodiments, the first direction (D1)109 and the second direction (D2) 105 may be considered in a horizontal(“X-Y”) plane. The third direction (D3) 111 may be considered in avertical (“Z”) plane. Hence, according to embodiments described herein,the access lines 103-1, 103-2, . . . , 103-Q are extending in a verticaldirection, e.g., third direction (D3) 111.

A memory cell, e.g., 110, may include an access device, e.g., accesstransistor, and a storage node, e.g., storage capacitor, located at anintersection of each access line 103-1, 103-2, . . . , 103-Q and eachdigit line 107-1, 107-2, . . . , 107-P. Memory cells may be written to,or read from, using the access lines 103-1, 103-2, . . . , 103-Q anddigit lines 107-1, 107-2, . . . , 107-P. The digit lines 107-1, 107-2, .. . , 107-P may conductively interconnect memory cells along horizontalcolumns of each sub cell array 101-, 101-2, . . . , 101-N, and theaccess lines 103-1, 103-2, . . . , 103-Q may conductively interconnectmemory cells along vertical rows of each sub cell array 101-1, 101-2, .. . , 101-N. One memory cell, e.g. 110, may be located between oneaccess line, e.g., 103-2, and one digit line, e.g., 107-2. Each memorycell may be uniquely addressed through a combination of an access line103-1, 103-2, . . . , 103-Q and a digit line 107-1, 107-2, . . . ,107-P.

The digit lines 107-1, 107-2, . . . , 107-P may be or include conductingpatterns (e.g., metal lines) disposed on and spaced apart from asubstrate. The digit lines 107-1, 107-2, . . . , 107-P may extend in afirst direction (D1) 109. The digit lines 107-1, 107-2, . . . , 107-P inone sub cell array, e.g., 101-2, may be spaced apart from each other ina vertical direction, e.g., in a third direction (D3) 111.

The access lines 103-1, 103-2, . . . , 103-Q may be or includeconductive patterns (e.g., metal lines) extending in a verticaldirection with respect to the substrate, e.g., in a third direction (D3)111. The access lines in one sub cell array, e.g., 101-2, may be spacedapart from each other in the first direction (D1) 109.

A gate of a memory cell, e.g., memory cell 110, may be connected to anaccess line, e.g., 103-2, and a first conductive node, e.g., firstsource/drain region, of an access device, e.g., transistor, of thememory cell 110 may be connected to a digit line, e.g., 107-2. Each ofthe memory cells, e.g., memory cell 110, may be connected to a storagenode, e.g., capacitor. A second conductive node, e.g., secondsource/drain region, of the access device, e.g., transistor, of thememory cell 110 may be connected to the storage node, e.g., capacitor.While first and second source/drain region reference are used herein todenote two separate and distinct source/drain regions, it is notintended that the source/drain region referred to as the “first” and/or“second” source/drain regions have some unique meaning. It is intendedonly that one of the source/drain regions is connected to a digit line,e.g., 107-2, and the other may be connected to a storage node.

FIG. 2 illustrates a perspective view showing a three dimensional (3D)semiconductor memory device, e.g., a portion of a sub cell array 101-2shown in FIG. 1 as a vertically oriented stack of memory cells in anarray, according to some embodiments of the present disclosure. FIG. 3illustrates a perspective view showing unit cell, e.g., memory cell 110shown in FIG. 1, of the 3D semiconductor memory device shown in FIG. 2.

As shown in FIG. 2, a substrate 200 may have formed thereon one of theplurality of sub cell arrays, e.g., 101-2, described in connection withFIG. 1. For example, the substrate 200 may be or include a siliconsubstrate, a germanium substrate, or a silicon-germanium substrate, etc.Embodiments, however, are not limited to these examples.

As shown in the example embodiment of FIG. 2, the substrate 200 may havefabricated thereon a vertically oriented stack of memory cells, e.g.,memory cell 110 in FIG. 1, extending in a vertical direction, e.g.,third direction (D3) 111. According to some embodiments the verticallyoriented stack of memory cells may be fabricated such that each memorycell, e.g., memory cell 110 in FIG. 1, is formed on plurality ofvertical levels, e.g., a first level (L1), a second level (L2), and athird level (L3). The repeating, vertical levels, L1, L2, and L3, may bearranged, e.g., “stacked”, a vertical direction, e.g., third direction(D3) 111 shown in FIG. 1, and separated from the substrate 200 by aninsulator material 220. Each of the repeating, vertical levels, L1, L2,and L3 may include a plurality of discrete components, e.g., regions, tothe laterally oriented access devices 230, e.g., transistors, andstorage nodes, e.g., capacitors, including access line 203-1, 203-2, . .. , 203-Q connections and digit line 207-1, 207-2, . . . , 207-Pconnections. The plurality of discrete components to the laterallyoriented access devices 230, e.g., transistors, may be formed in aplurality of iterations of vertically, repeating layers within eachlevel, as described in more detail below in connection with FIGS. 4A-4Fand may extend horizontally in the second direction (D2) 205, analogousto second direction (D2) 105 shown in FIG. 1.

The plurality of discrete components to the laterally oriented accessdevices 230, e.g., transistors, may include a first source/drain region221 and a second source/drain region 223 separated by a channel and bodyregion 225, extending laterally in the second direction (D2) 205, andformed in a body of the access devices. In some embodiments, the channelregion 225 may include silicon, germanium, silicon-germanium, and/orindium gallium zinc oxide (IGZO). In some embodiments, the first and thesecond source/drain regions, 221 and 223, can include an n-type dopantregion formed in a p-type doped body to the access device to form ann-type conductivity transistor. In some embodiments, the first and thesecond source/drain regions, 221 and 223, may include a p-type dopantformed within an n-type doped body to the access device to form a p-typeconductivity transistor. By way of example, and not by way oflimitation, the n-type dopant may include Phosphorous (P) atoms and thep-type dopant may include atoms of Boron (B) formed in an oppositelydoped body region of polysilicon semiconductor material. Embodiments,however, are not limited to these examples.

The storage node 227, e.g., capacitor, may be connected to onerespective end of the access device. As shown in FIG. 2, the storagenode 227, e.g., capacitor may be connected to the second source/drainregion 223 of the access device. The storage node may be or includememory elements capable of storing data. Each of the storage nodes maybe a memory element using one of a capacitor, a magnetic tunnel junctionpattern, and/or a variable resistance body which includes a phase changematerial, etc. Embodiments, however, are not limited to these examples.In some embodiments, the storage node associated with each access deviceof a unit cell, e.g., memory cell 110 in FIG. 1, may similarly extend inthe second direction (D2) 205, analogous to second direction (D2) 105shown in FIG. 1.

As shown in FIG. 2 a plurality of horizontally oriented digit lines207-1, 207-2, . . . , 207-P extend in the first direction (D1) 209,analogous to the first direction (D1) 109 in FIG. 1. The plurality ofhorizontally oriented digit lines 207-1, 207-2, . . . , 207-P may beanalogous to the digit lines 107-1, 107-2, . . . , 107-P shown inFIG. 1. The plurality of horizontally oriented digit lines 207-1, 207-2,. . . , 207-P may be arranged, e.g., “stacked”, along the thirddirection (D3) 211. The plurality of horizontally oriented digit lines207-1, 207-2, . . . , 207-P may include a conductive material. Forexample, the conductive material may include one or more of a dopedsemiconductor, e.g., doped silicon, doped germanium, etc., a conductivemetal nitride, e.g., titanium nitride, tantalum nitride, etc., a metal,e.g., tungsten (W), titanium (Ti), tantalum (Ta), etc., and/or ametal-semiconductor compound, e.g., tungsten silicide, cobalt silicide,silver silicide, titanium silicide, etc. Embodiments, however, are notlimited to these examples.

Among each of the vertical levels, (L1) 213-1, (L2) 213-2, and (L3)213-M, the horizontally oriented memory cells, e.g., memory cell 110 inFIG. 1, may be spaced apart from one another horizontally in the firstdirection (D1) 209. However, as described in more detail below inconnection with FIGS. 4A-4E, the plurality of discrete components to thelaterally oriented access devices 230, e.g., first source/drain region221 and second source/drain region 223 separated by a channel and bodyregion 225, extending laterally in the second direction (D2) 205, andthe plurality of horizontally oriented digit lines 207-1, 207-2, . . . ,207-P extending laterally in the first direction (D1) 209, may be formedwithin different vertical layers within each level. For example, theplurality of horizontally oriented digit lines 207-1, 207-2, . . . ,207-P, extending in the first direction (D1) 209, may be disposed on,and in electrical contact with, top surfaces of first source/drainregions 221 and orthogonal to laterally oriented access devices 230,e.g., transistors, extending in laterally in the second direction (D2)205. In some embodiments, the plurality of horizontally oriented digitlines 207-1, 207-2, . . . , 207-P, extending in the first direction (D1)209 are formed in a higher vertical layer, farther from the substrate200, within a level, e.g., within level (L1), than a layer in which thediscrete components, e.g., first source/drain region 221 and secondsource/drain region 223 separated by a channel and body region 225, ofthe laterally oriented access device are formed. In some embodiments,the plurality of horizontally oriented digit lines 207-1, 207-2, . . . ,207-P, extending in the first direction (D1) 209, may be connected tothe top surfaces of the first source/drain regions 221 directly and/orthrough additional contacts including metal silicides.

As shown in the example embodiment of FIG. 2, the access lines, 203-1,203-2, . . . , 203-Q, extend in a vertical direction with respect to thesubstrate 200, e.g., in a third direction (D3) 211. Further, as shown inFIG. 2, the access lines, 203-1, 203-2, . . . , 203-Q, in one sub cellarray, e.g., sub cell array 101-2 in FIG. 1, may be spaced apart fromeach other in the first direction (D1) 209. The access lines, 203-1,203-2, . . . , 203-Q, may be provided, extending vertically relative tothe substrate 200 in the third direction (D3) 211 between a pair of thelaterally oriented access devices 230, e.g., transistors, extendinglaterally in the second direction (D2) 205, but adjacent to each otheron a level, e.g., first level (L1), in the first direction (D1) 209.Each of the access lines, 203-1, 203-2, . . . , 203-Q, may verticallyextend, in the third direction (D3), on sidewalls of respective ones ofthe plurality of laterally oriented access devices 230, e.g.,transistors, that are vertically stacked.

For example, and as shown in more detail in FIG. 3, a first one of thevertically extending access lines, e.g., 203-1, may be adjacent asidewall of a channel and body region 225 to a first one of thelaterally oriented access devices 230, e.g., transistors, in the firstlevel (L1) 213-1, a sidewall of a channel and body region 225 of a firstone of the laterally oriented access devices 230, e.g., transistors, inthe second level (L2) 213-2, and a sidewall of a channel and body region225 of a first one of the laterally oriented access devices 230, e.g.,transistors, in the third level (L3) 213-M, etc. Similarly, a second oneof the vertically extending access lines, e.g., 203-2, may be adjacent asidewall to a channel and body region 225 of a second one of thelaterally oriented access devices 230, e.g., transistors, in the firstlevel (L1) 213-1, spaced apart from the first one of laterally orientedaccess devices 230, e.g., transistors, in the first level (L1) 213-1 inthe first direction (D1) 209. And the second one of the verticallyextending access lines, e.g., 203-2, may be adjacent a sidewall of achannel and body region 225 of a second one of the laterally orientedaccess devices 230, e.g., transistors, in the second level (L2) 213-2,and a sidewall of a channel and body region 225 of a second one of thelaterally oriented access devices 230, e.g., transistors, in the thirdlevel (L3) 213-M, etc. Embodiments are not limited to a particularnumber of levels.

The vertically extending access lines, 203-1, 203-2, . . . , 203-Q, mayinclude a conductive material, such as, for example, one of a dopedsemiconductor material, a conductive metal nitride, metal, and/or ametal-semiconductor compound. The access lines, 203-1, 203-2, . . . ,203-Q, may correspond to word lines (WL) described in connection withFIG. 1.

As shown in the example embodiment of FIG. 2, a conductive body contact250 may be formed extending in the first direction (D1) 209 along an endsurface of the laterally oriented access devices 230, e.g., transistors,in each level (L1) 213-1, (L2) 213-2, and (L3) 213-M above the substrate200. The body contact 250 may be connected to a body 226, e.g., bodyregion, of the laterally oriented access devices 230, e.g., transistors,in each memory cell, e.g., memory cell 110 in FIG. 1. The body contact250 may include a conductive material such as, for example, one of adoped semiconductor material, a conductive metal nitride, metal, and/ora metal-semiconductor compound.

Although not shown in FIG. 2, an insulating material may fill otherspaces in the vertically stacked array of memory cells. For example, theinsulating material may include one or more of a silicon oxide material,a silicon nitride material, and/or a silicon oxynitride material, etc.Embodiments, however, are not limited to these examples.

FIG. 3 illustrates in more detail a unit cell, e.g., memory cell 110 inFIG. 1, of the vertically stacked array of memory cells, e.g., within asub cell array 101-2 in FIG. 1, according to some embodiments of thepresent disclosure. As shown in FIG. 3, the first and the secondsource/drain regions, 321 and 323, may be impurity doped regions to thelaterally oriented access devices 330, e.g., transistors. The first andthe second source/drain regions, 321 and 323, may be analogous to thefirst and the second source/drain regions 221 and 223 shown in FIG. 2.The first and the second source/drain regions may be separated by achannel and body region 325 formed in a body of semiconductor material,e.g., body region 326, of the laterally oriented access devices 230,e.g., transistors. The first and the second source/drain regions, 321and 323, may be formed from an n-type or p-type dopant doped in the bodyregion 326. Embodiments are not so limited.

For example, for an n-type conductivity transistor construction the bodyregion 326 of the laterally oriented access devices 230, e.g.,transistors, may be formed of a low doped (p−) p-type semiconductormaterial. In one embodiment, the body region 326 and the channel 325separating the first and the second source/drain regions, 321 and 323,may include a low doped, p-type (e.g., low dopant concentration (p−))polysilicon material consisting of Boron (B) atoms as an impurity dopantto the polycrystalline silicon. In this example, the first and thesecond source/drain regions, 321 and 321, may include a high dopantconcentration, n-type conductivity impurity (e.g., high dopant (n+))doped in the first and the second source/drain regions, 321 and 323. Insome embodiments, the high dopant, n-type conductivity first and seconddrain regions 321 and 323 may include a high concentration of Phosphorus(P) atoms deposited therein. Embodiments, however, are not limited tothis example. In other embodiments, the laterally oriented accessdevices 230, e.g., transistors, may be of a p-type conductivityconstruction in which case the impurity, e.g., dopant, conductivitytypes would be reversed.

As shown in the example embodiment of FIG. 3, the first source/drainregion 321 may occupy an upper portion in the body 326 of the laterallyoriented access devices 330, e.g., transistors. For example, the firstsource/drain region 321 may have a bottom surface 324 within the body326 of the laterally oriented access device 330 which is located higher,vertically in the third direction (D3) 311, than a bottom surface of thebody 326 of the laterally, horizontally oriented access device 330. Assuch, the laterally, horizontally oriented transistor 330 may have abody portion 326 which is below the first source/drain region 321 and isin electrical contact with the body contact, e.g., 250 shown in FIG. 2.Further, as shown in the example embodiment of FIG. 3, a digit line,e.g., 307-1, analogous to the digit lines 207-1, 207-2, . . . , 207-P inFIG. 2 and 107-1, 107-2, . . . , 107-P shown in FIG. 1, may disposed ona top surface 322 of the first source/drain region 321 and electricallycoupled thereto.

As shown in the example embodiment of FIG. 3, an access line, e.g.,303-1, analogous to the access lines 203-1, 203-2, . . . , 203-Q in FIG.2 and 103-1, 103-2, . . . , 103-Q in FIG. 1, may be vertically extendingin the third direction (D3) 311 adjacent sidewall of the channel region325 portion of the body 326 to the laterally oriented access devices330, e.g., transistors horizontally conducting between the first and thesecond source/drain regions 321 and 323 along the second direction (D2)305. A gate dielectric material 304 may be interposed between the accessline 303-1 (a portion thereof forming a gate to the laterally orientedaccess devices 330, e.g., transistors) and the channel region 325. Thegate dielectric material 304 may include, for example, a high-kdielectric material, a silicon oxide material, a silicon nitridematerial, a silicon oxynitride material, etc., or a combination thereof.Embodiments are not so limited. For example, in high-k dielectricmaterial examples the gate dielectric material 304 may include one ormore of hafnium oxide, hafnium silicon oxide, lanthanum oxide, zirconiumoxide, zirconium silicon oxide, tantalum oxide, titanium oxide, bariumstrontium titanium oxide, barium titanium oxide, strontium titaniumoxide, lithium oxide, aluminum oxide, lead scandium tantalum oxide, leadzinc niobite, etc.

FIGS. 4A-4F are cross-sectional views for forming arrays of verticallystacked memory cells, at multiple stages of a semiconductor fabricationprocess, to form a channel and body region for semiconductor devices, inaccordance with a number of embodiments of the present disclosure.

FIG. 4A is a cross-sectional view, at one stage of the semiconductorfabrication process, for forming arrays of vertically stacked memorycells, to form a channel and body region of a horizontally orientedaccess device, e.g., transistor, in accordance with a number ofembodiments of the present disclosure.

In the example embodiment shown in FIG. 4A, the method comprisesdepositing alternating layers of a first dielectric material, 430-1,430-2, . . . , 430-N (collectively referred to as first dielectricmaterial 430), a semiconductor material, 432-1, 432-2, . . . , 432-N(collectively referred to as semiconductor material 432), and a seconddielectric material, 433-1, 433-2, . . . , 433-N (collectively referredto as second dielectric 433), in repeating iterations to form a verticalstack 401 on a working surface of a semiconductor substrate 400. In someembodiments, the first dielectric material 430, the semiconductormaterial 432, and the second dielectric material 433 may be depositedusing a chemical vapor deposition (CVD) process. In one embodiment, thefirst dielectric material 430 can be deposited to have a thickness,e.g., vertical height in the third direction (D3), in a range of twenty(20) nanometers (nm) to sixty (60) nm. In one embodiment, thesemiconductor material 432 can be deposited to have a thickness, e.g.,vertical height, in a range of twenty (20) nm to one hundred (100) nm.In one embodiment, the second dielectric material 433 can be depositedto have a thickness, e.g., vertical height, in a range of ten (10) nm tothirty (30) nm. Embodiments, however, are not limited to these examples.As shown in FIGS. 4A-4F, a vertical direction 411 is illustrated as athird direction (D3), e.g., z-direction in an x-y-z coordinate system,analogous to the third direction (D3) among first, second, and thirddirections, shown in FIGS. 1-3.

In some embodiments, the first dielectric material, 430-1, 430-2, . . ., 430-N, may be an interlayer dielectric (ILD). By way of example, andnot by way of limitation, the first dielectric material, 430-1, 430-2, .. . , 430-N, may comprise an oxide material, e.g., SiO₂. In anotherexample the first dielectric material, 430-1, 430-2, . . . , 430-N, maycomprise a silicon nitride (Si₃N₄) material (also referred to herein as“SiN”). In another example the first dielectric material, 430-1, 430-2,. . . , 430-N, may comprise a silicon oxy-carbide (SiO_(x)C_(y))material. In another example the first dielectric material, 430-1,430-2, . . . , 430-N, may include silicon oxy-nitride (SiO_(x)N_(y))material (also referred to herein as “SiON”), and/or combinationsthereof. Embodiments are not limited to these examples.

In some embodiments the semiconductor material, 432-1, 432-2, . . . ,432-N, may comprise a silicon (Si) material in a polycrystalline and/oramorphous state. The semiconductor material, 432-1, 432-2, . . . ,432-N, may be a low doped, p-type (p−) silicon material. Thesemiconductor material, 432-1, 432-2, . . . , 432-N, may be formed bygas phase doping boron atoms (B), as an impurity dopant, at a lowconcentration to form the low doped, p-type (p−) silicon material. Insome embodiments, the semiconductor material 432-1, 432-2, . . . , 432-Nmay be formed by gas phase doping boron atoms (B) in-situ. The lowdoped, p-type (p−) silicon material may be an amorphous siliconmaterial. Embodiments, however, are not limited to these examples.

In some embodiments, the second dielectric material, 433-1, 433-2, . . ., 433-N, may be an interlayer dielectric (ILD). By way of example, andnot by way of limitation, the second dielectric material, 433-1, 433-2,. . . , 433-N, may comprise a nitride material. The nitride material maybe a silicon nitride (Si₃N₄) material (also referred to herein as“SiN”). In another example the second dielectric material, 433-1, 433-2,. . . , 433-N, may comprise a silicon oxy-carbide (SiOC) material. Inanother example the second dielectric material, 433-1, 433-2, . . . ,433-N, may include silicon oxy-nitride (SiON), and/or combinationsthereof. Embodiments are not limited to these examples. However,according to embodiments, the second dielectric material, 433-1, 433-2,. . . , 433-N, is purposefully chosen to be different in material orcomposition than the first dielectric material, 430-1, 430-2, . . . ,430-N, such that a selective etch process may be performed on one of thefirst and second dielectric layers, selective to the other one of thefirst and the second dielectric layers, e.g., the second SiN dielectricmaterial, 433-1, 433-2, . . . , 433-N, may be selectively etchedrelative to the semiconductor material, 432-1, 432-2, . . . , 432-N, anda first oxide dielectric material, 430-1, 430-2, . . . , 430-N.

Again, the repeating iterations of alternating first dielectricmaterial, 430-1, 430-2, . . . , 430-N layers, semiconductor material,432-1, 432-2, . . . , 432-N layers, and second dielectric material,433-1, 433-2, . . . , 433-N layers may be deposited according to asemiconductor fabrication process such as chemical vapor deposition(CVD) in a semiconductor fabrication apparatus. Embodiments, however,are not limited to this example and other suitable semiconductorfabrication techniques may be used to deposit the alternating layers ofa first dielectric material, a semiconductor material, and a seconddielectric material, in repeating iterations to form the vertical stack401.

The layers may occur in repeating iterations vertically. In the exampleof FIG. 4A, three tiers, numbered 1, 2, and 3, of the repeatingiterations are shown. For example, the stack may include: a firstdielectric material 430-1, a semiconductor material 432-1, a seconddielectric material 433-1, a third dielectric material 430-2, a secondsemiconductor material 432-2, a fourth dielectric material 433-2, afifth dielectric material 430-3, a third semiconductor material 432-3,and a sixth dielectric material 433-3. As such, a stack may include: afirst oxide material 430-1, a first semiconductor material 432-1, afirst nitride material 433-1, a second oxide material 430-2, a secondsemiconductor material 432-2, a second nitride material 433-2, a thirdoxide material 430-3, a third semiconductor material 432-3, and a thirdnitride material 433-3 in further repeating iterations. Embodiments,however, are not limited to this example and more or fewer repeatingiterations may be included.

FIG. 4B is a is a cross-sectional view, at another stage of thesemiconductor fabrication process, for forming arrays of verticallystacked memory, cells to form a channel and body region of ahorizontally oriented access device, e.g., transistor, in accordancewith a number of embodiments of the present disclosure.

According to embodiments, the semiconductor fabrication processdescribed in FIGS. 4B-4F can occur after an elongated pillar extendingpredominantly in a second direction and access line formation such asshown in FIGS. 5A-6E have been performed. According to embodiments, themethods in FIG. 4A-4F can convert the semiconductor material 432, e.g.,a low doped (p−) polysilicon material, to a single crystallinestructure.

As shown in FIG. 4B, a vertical opening 471 may be formed through thelayers within the vertically stacked memory cells to expose verticalsidewalls in the vertical stack 401. The opening 471 may be formedthrough the alternating in repeating iterations using a first etchantprocess to form the opening 471 adjacent a first region, e.g., 742 inFIG. 7C, of the semiconductor material 432, e.g., poly-silicon(poly-Si). The vertical opening 471 may be formed through the repeatingiterations of the oxide material 430, the semiconductor material 432,and the nitride material 433. As such, the vertical opening 471 may beformed through the first oxide material 430-1, the first semiconductormaterial 432-1, the first nitride material 433-1, the second oxidematerial 430-2, the second semiconductor material 432-2, the secondnitride material 433-2, the third oxide material 430-3, the thirdsemiconductor material 432-3, and the third nitride material 433-3.Embodiments, however, are not limited to the single vertical opening 471shown in FIG. 4B. Multiple vertical openings may be formed through thelayers of materials. The vertical opening 471 may be formed to exposevertical sidewalls in the vertical stack 401. In one example, a workingsurface of the substrate 400 may be masked and patterned to form thevertical opening 471 to have a width in a range of fifty (50) nanometers(nm) to five hundred (500) nm and a depth in a range of five hundred(500) nm to twenty thousand (20,000) nm. Embodiments, however, are notlimited to this example.

FIG. 4C is a cross-sectional view, at another stage of the semiconductorfabrication process, for forming arrays of vertically stacked memorycells having vertically oriented access lines, to form a channel andbody region of a horizontally oriented access device, in accordance witha number of embodiments of the present disclosure.

As shown in FIG. 4C, a metal, e.g., seed, material 416 may be depositedover the vertical stack 401, the sidewalls of the vertical opening 471,and the bottom of the vertical opening 471. In some embodiments, themetal material 416 may be deposited using an atomic layer deposition(ALD) process. In one embodiment the metal material 416 is a nickel (Ni)metal material 416. In this example the nickel (Ni) metal material 416may be selectively deposited to form a Ni silicide (NiSi) 416 with thesilicon material 432. In one example, the metal material 416, e.g., seedmaterial, may be deposited to a thickness (t1) in a range ofapproximately 5-50 angstroms (Å). Embodiments, however, are not limitedto these examples. In some embodiments, the metal material 416 comprisesa metal that can form a silicide with a silicon (Si) material, e.g.,polysilicon material 432.

FIG. 4D is a cross-sectional view, at another stage of the semiconductorfabrication process, for forming arrays of vertically stacked memorycells having vertically oriented access lines, to form a channel andbody region for a horizontally oriented access device, in accordancewith a number of embodiments of the present disclosure.

In the example embodiment of FIG. 4D, the vertical stack 401 may beprocessed under temperature, pressure, and time parameters such that asthe metal material 416 advances horizontally within a portion of thesemiconductor material 432 and transforms the crystalline structure ofthe portion of the semiconductor material 432 into a large grain sizepoly crystalline material 417, e.g., monocrystalline semiconductormaterial, according to a metal induced lateral crystalline (MILC), solidphase crystallization (SPC) process. As the metal material 416 advancesthrough the semiconductor material 432 as a result of an annealingprocess at elevated temperatures, the metal material 416 may acquiresilicon atoms from the semiconductor material 432 and become a metalsilicide material 415. In some embodiments, the metal silicide material415 may be a Nickel silicide material, a Cobalt silicide material, or aSilver silicide material. The metal silicide material 415 may advancethrough the semiconductor material 432 as a result of a chemicalreaction between the metal silicide material 415 and the semiconductormaterial 432. The speed at which the metal silicide material 415advances through the semiconductor material 432 may be controlled byadjusting the temperature applied to the vertical stack 401 and themetal silicide material 415. In some embodiments, the vertical stack 401is processed at a temperature in a range of 400 to 600 degrees Celsius(° C.) such that the metal silicide material 415 advances horizontallythrough the semiconductor material 432, e.g., poly-silicon, transformingthe portion of the semiconductor material 432 to monocrystallinesemiconductor material 417.

In some embodiments, a distance (DIST1) to which the metal silicidematerial 415 advances horizontally within the portion of thesemiconductor material 432 is determined by a number of factors such asa thickness (H1), e.g., vertical height, of the semiconductor material432 layer, a thickness of the metal material, e.g., seed material,deposited on the vertical sidewalls, and first region of thesemiconductor material 432, in the vertical opening 471 of the verticalstack 401, and a temperature. In some embodiments, the distance (DIST1)to which the metal silicide material 415 advances horizontally withinthe portion of the semiconductor material 432, transforming the portionof the semiconductor material 432 to monocrystalline semiconductormaterial 417, may be controlled by adjusting the temperature applied tothe vertical stack 401 and the metal silicide material 415 in theprocess, as well as adjusting the amount of time in which thattemperature is applied.

In some embodiments, at an applied temperature of less than 600 degreesCelsius (° C.), a thickness (H1), e.g., vertical height, of thesemiconductor material 432 layer in a range of twenty (20) nm to onehundred (100) nm, and for a metal material 416, e.g., seed material,deposited to a thickness (t1) in a range of approximately 5-50 angstroms(Å), the time and process parameters are controlled such that the metalsilicide 415 advances horizontally through the silicon material 432,transforming the portion of the semiconductor material 432 tomonocrystalline semiconductor material 417, a first distance (DIST1) ina range of 100 nanometers (nm) to 300 nm. In one embodiment, the metalsilicide 415 advances horizontally through the silicon material 432,transforming the portion of the semiconductor material 432 to a largegrain polycrystalline silicon and/or monocrystalline silicon structure417, a first distance (DIST1) of at least 200 nanometers (nm). In someembodiments, the process may be performed, under the design rulesdescribed herein, at a temperature as low as 400 degrees Celsius (° C.).

In some embodiments, under the above described process parameters, themetal silicide 415 advances in a diagonal-horizontal progression throughthe silicon material 432, transforming the portion of the semiconductormaterial 432 to a large grain polycrystalline silicon and/ormonocrystalline silicon structure 417. However, such diagonal-horizontaladvancement is bounded by the first dielectric material 430, e.g., asfloor in a vertical direction (third direction (D3), and by the seconddielectric material 433, e.g., as a ceiling in a vertical direction,such that the advancement of the metal silicide 415 continues toprogress horizontally in a second direction (D2) for a distance (DIST1)and at a height (H1) within the semiconductor material 432, transformingthe portion of the semiconductor material 432 to a large grainpolycrystalline silicon and/or monocrystalline silicon structure 417, ina direction moving away from the vertical opening 471.

In some embodiments, the metal 416, e.g., seed material, may bedeposited in a second vertical opening, e.g., 751 in FIG. 7C, throughthe vertical stack 400 which is opened in a second region, e.g., 744 in7C, to eventually form storage nodes. Using a similar process andprocessing parameter control techniques to those described above, aresulting metal silicide 415 may progress horizontally through thesemiconductor material 432 in a direction moving away from the secondvertical opening, e.g., 751 in FIG. 7C, which is a side of the verticalstack 401 that will include a storage node to be formed adjacent and inthe second vertical opening and in the second region, e.g., 744. Inthese embodiments, the metal silicide material 415 may move through thesemiconductor material 432 in a direction toward the first opening 471.Embodiments, however, are not limited to these examples.

In one embodiment, the metal silicide 415 continues to progresshorizontally in a second direction (D2) for a distance (DIST1) and at aheight (H1) within the semiconductor material 432, transforming theportion of the semiconductor material 432 to a large grainpolycrystalline silicon and/or monocrystalline silicon structure 417,along a <100> crystalline plane orientation or a crystalline planeorientation that is close to a <100> crystalline plane orientation.Embodiments, however, are not limited to this example. In someembodiments, a better monocrystalline uniformity is achieved a furtherdistance the metal silicide 415 progresses from the initial metal 416,e.g., seed material, deposition location.

According to some embodiments, the resulting, transformed portion of thesilicon crystalline material 417 is a substantially monocrystallinesilicon structure such that grain boundaries (GB) of the crystallinestructure are mostly sub-grain boundaries (sub-GB) and such that thetransformed portion of the silicon crystalline material 417 hasapproximately less than (<) one degree (1°) of crystalline orientationdifference. In one embodiment, the large grain polycrystalline and/orsubstantially monocrystalline silicon crystalline material 417 has aconcentration of grain boundary defects of less than one defect in1×10¹⁸ cubic centimeters (also referred to as centimeters cubed (cm³).For example, according to embodiments, the vertical stack 401 may beprocessed under temperature, deposition thickness, and time parametersto horizontally advance the metal silicide 415, recrystallizing thepolysilicon and/or amorphous silicon semiconductor material 432 into asubstantially monocrystalline silicon structure 417 having mostlysub-grain boundaries (sub-GB). Stated otherwise, according toembodiments described herein, the poly and/or amorphous siliconsemiconductor material 432 is recrystallized into a substantiallymonocrystalline silicon structure 417 such that grain boundaries withinthe monocrystalline silicon structure 417 have a crystalline orientationdifference of less than one degree (1°). Again, in some embodiments, thedefect density of the monocrystalline silicon structure 417 may be lessthan one defect in 1×10¹⁸ centimeters cubed (cm³) of the monocrystallinesilicon structure 417.

In result, a better crystalline structure for a channel and body regionof a horizontally oriented access device is provided with betterelectron mobility due to large grain size and low grain boundary (GB)density. For example, a lower GB trap density may be realized, and lesselectron hole pair generation may occur resulting in a lower “off”current (“Ioff”) for the horizontally oriented access device under thedescribed design rules and scale. Also, better uniformity, with animproved tail bit growth profile, may be achieved as compared to otherlow temperature chemical vapor deposition (CVD) of amorphoussilicon:hydrogen (a-Si:H) film deposition processes in forming, e.g.,depositing, the semiconductor material 432.

As noted, in some embodiments, the metal material 415 may transform thesemiconductor material 432 into the crystalline material 417 using metalinduced lateral crystallization (MILC). MILC may be a more effectiveprocess of recrystallization when applied to amorphous silicon incomparison to applying MILC to polysilicon. MILC may be less effectivewhen it is applied to polysilicon because the grain boundaries inpolysilicon may impede the movement of a metal silicide, e.g., metalsilicide material 415, through the polysilicon during therecrystallization process. Due to the grain boundaries in thepolysilicon material impeding the movement of the metal silicide throughthe polysilicon material, the speed of the crystal growth in thepolysilicon material during MILC may be slower than the speed of crystalgrowth in amorphous silicon material during MILC. Further, polysiliconis more stable than amorphous silicon, therefore, the amount of energyrequired to recrystallize polysilicon is greater than the amount ofenergy required to recrystallize amorphous silicon.

In some embodiments, the MILC may occur at a temperature less than 450degrees ° C. In some embodiments, the metal silicide material 415 maytransform the semiconductor material 432 into the crystalline material417 using solid phase crystallization (SPC). The vertical stack 401 maybe processed under temperature and time parameters such that, as themetal silicide material 415 advances within the semiconductor material432, it transforms the crystalline structure of a portion of thesemiconductor material 432 according to increasing a size of individualcrystals in that portion of the semiconductor material 432.

After advancing through the semiconductor material 432, the verticalstack 401 may be processed to form other semiconductor components, e.g.,storage nodes, digit lines, vertical access lines, etc., and/or discreteregions such as source/drain regions. In some embodiments, and by way ofexample and not by way of limitation, the metal silicide material 415that remains has a very low defect concentration and/or impurity.Further, as the metal silicide 415 advances through the silicon material432 a first distance, e.g., DIST1, it may provide a dividing interfacebetween the monocrystalline silicon 417 and the remaining,un-transformed and/or recrystallized semiconductor material 432, e.g.,amorphous silicon, wherein the crystals of the monocrystalline side ofthe interface are larger than the crystals in the amorphous siliconstructure 432 and such that after crystallization very low metalimpurity from the metal material 416, e.g., seed material, remains inthe semiconductor material 432, e.g., polysilicon.

As will be described in more detail below, the recrystallizedmonocrystalline silicon structure 417 may be used in the first regionfor formation of a horizontally oriented access device in the verticalstack 401. In some embodiments, the remaining metal silicide material415, now a first distance (D1) from the vertical opening 471, may serveas an etch stop while selectively removing the semiconductor material432 from a second region of the vertical stack 401 for formation of astorage node. For example, a horizontal capacitor cell may be formed inthe selectively removed semiconductor material 432 in the second regionusing an ALD process.

As noted, the vertical stack 401 is processed such that the metalsilicide material 415 advances horizontally through the silicon materiala first distance (DIST1) and provides a dividing interface between thetransformed, monocrystalline silicon 417 and the crystalline structureof the remaining semiconductor material 432. The crystals on themonocrystalline side 417 of the interface are larger than the crystalsin the remaining semiconductor material 432 structure. Due to the largercrystals in the transformed material 417 in comparison to a non-metalsilicide formation process, e.g., MILC/SPC process, for the remainingamorphous and/or poly-silicon semiconductor material 432, thetransformed crystalline material 417 may provide an improved channel andbody region, e.g., 325 in FIG. 3, with better electron mobility and less“off” current (“Ioff”) leakage than a channel and body region formedusing the deposited semiconductor material 432. Again, in someembodiments, a thickness (H1), e.g., vertical height, of a channel andbody region (325 in FIG. 3) formed from the transformed crystallinematerial 417 may be in a range of approximately twenty (20) nm to onehundred (100) nm. In some embodiments, the remaining, non-transformed,semiconductor material 432, on the side of the interface in a horizontaldirection away from the vertical opening 471, may be sacrificiallyremoved to form a horizontal opening for formation of a horizontallyoriented storage node for the vertically stacked memory cells havingvertically oriented access lines. For example, in some embodiments, anyremaining metal silicide material 415 may be used as an etch stop tosacrificial removal of the semiconductor material 432 and/or as an ohmiccontact to a first electrode of a capacitor formed in a second region ofthe vertical stack 401 as a storage node.

FIG. 4E is a cross-sectional view, at another stage of the semiconductorfabrication process, for forming arrays of vertically stacked memorycells, to form a channel and body region of a horizontally orientedaccess device, in accordance with a number of embodiments of the presentdisclosure.

As shown in the example of FIG. 4E, the metal material 416 that did notadvance within the semiconductor material 432 may remain on verticalsidewalls of the first dielectric material 430 and the second dielectricmaterial 433 in the vertical opening 471 and on a bottom surface of thevertical opening 471 of the vertical stack 401 as can be seen in FIG.4D. Therefore, in one embodiment, as shown in FIG. 4E, an isotropic etchprocess clean may be performed in the vertical opening 471 on thevertical stack 401, e.g., on the sidewalls and bottom of the verticalopening 471 to remove residual, remaining metal material 416 from thosesurfaces. Removing the metal material 416 from such surfaces in thevertical opening 471 of the vertical stack 401, e.g., sidewalls andbottom of the vertical opening 471, may preserve an original aspectratio (A/R), vertical height to width ratio, of the vertical opening 471for subsequent material deposition therein in subsequent semiconductorfabrication processes described herein. In some embodiments, the A/R maybe in a range of ten (10) to forty (40). In some embodiments, the A/Rmay be in a range of 40 nm to 150 nm.

FIG. 4F is a cross-sectional view, at another stage of the semiconductorfabrication process, for forming arrays of vertically stacked memorycells, to form a channel and body region of a horizontally orientedaccess device, in accordance with a number of embodiments of the presentdisclosure.

As shown in the example embodiment of FIG. 4F, subsequent semiconductorfabrication processes may be performed to selectively remove asacrificial portion of the second dielectric material 433, use gas phasedoping to deposit a first source/drain region in a top surface of thetransformed, crystalline material 417, deposit a conductive digit linematerial in electrical contact with the first source/drain region,provide an isolation barrier, and deposit a body contact 495 material inthe vertical opening to form a device structure as shown in FIG. 3.

In the example of FIG. 4F, the digit lines 477 may be horizontallyoriented digit lines 477, 207 shown in FIG. 2, extending in a firstdirection (D1), running in to and out from the plane of the drawingsheet in FIG. 4F. One example of forming a first source/drain region ina top surface of the transformed, crystalline material 417, a conductivedigit line material in electrical contact with the first source/drainregion, an isolation barrier, and a body contact 495 material isdescribed in co-pending U.S. patent application Ser. No. 16/943,494,entitled “Digit Line and Body Contact for Semiconductor Devices”, havingat least one common inventor, and filed on Jul. 30, 2020. Anotherexample is provided in co-pending U.S. patent application Ser. No.16/943,163, entitled “Underbody Contact to Horizontal Access Devices forVertical Three-Dimensional (3D) Memory”, having at least one commoninventor, and filed on Jul. 30, 2020. Another example is provided inco-pending U.S. patent application Ser. No. 16/943,108, entitled “DigitLine Formation for Horizontally Oriented Access Devices”, having atleast one common inventor, and filed on Jul. 30, 2020. All of which areincorporated in full herein by reference.

FIG. 5A illustrate an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices and vertically oriented access lines, in accordance with anumber of embodiments of the present disclosure. FIG. 5A illustrates atop down view of a semiconductor structure, at a particular point intime, in a semiconductor fabrication process, according to one or moreembodiments. In the example embodiment shown in the example of FIG. 5A,the method comprises using an etchant process to form a plurality offirst vertical openings 500, having a first horizontal direction (D1)509 and a second horizontal direction (D2) 505, through the verticalstack to the substrate. In one example, as shown in FIG. 5A, theplurality of first vertical openings 500 are extending predominantly inthe second horizontal direction (D2) 505 and may form elongatedvertical, pillar columns 513 with sidewalls 514 in the vertical stack.The plurality of first vertical openings 500 may be formed usingphotolithographic techniques to pattern a photolithographic mask 535,e.g., to form a hard mask (HM), on the vertical stack prior to etchingthe plurality of first vertical openings 500.

FIG. 5B is a cross sectional view, taken along cut-line A-A′ in FIG. 5A,showing another view of the semiconductor structure at a particular timein the semiconductor fabrication process. The cross sectional view shownin FIG. 5B shows the repeating iterations of alternating layers of afirst dielectric material, 530-1, 530-2, . . . , 530-N, a semiconductormaterial, 532-1, 532-2, . . . , 532-N, and a second dielectric material,533-1, 533-2, . . . , 533-N, on a semiconductor substrate 500 to formthe vertical stack, e.g. 401 as shown in FIG. 4. FIG. 5B illustratesthat a conductive material, 540-1, 540-2, . . . , 540-4, may be formedon a gate dielectric material 538 in the plurality of first verticalopenings 500. By way of example and not by way of limitation, a gatedielectric material 538 may be conformally deposited in the plurality offirst vertical openings 500 using a chemical vapor deposition (CVD)process, plasma enhanced CVD (PECVD), atomic layer deposition (ALD), orother suitable deposition process, to cover a bottom surface and thevertical sidewalls of the plurality of first vertical openings. The gatedielectric 538 may be deposited to a particular thickness (t1) as suitedto a particular design rule, e.g., a gate dielectric thickness ofapproximately 10 nanometers (nm). Embodiments, however, are not limitedto this example. By way of example, and not by way of limitation, thegate dielectric 538 may comprise a silicon dioxide (SiO₂) material,aluminum oxide (Al₂O₃) material, high dielectric constant (k), e.g.,high-k, dielectric material, and/or combinations thereof as alsodescribed in FIG. 3.

Further, as shown in FIG. 5B, a conductive material, 540-1, 540-2, . . ., 540-4, may be conformally deposited in the plurality of first verticalopenings 500 on a surface of the gate dielectric material 538. By way ofexample, and not by way of limitation, the conductive material, 540-1,540-2, . . . , 540-4, may be conformally deposited in the plurality offirst vertical openings 500 on a surface of the gate dielectric material538 using a chemical vapor deposition process (CVD), plasma enhanced CVD(PECVD), atomic layer deposition (ALD), or other suitable depositionprocess, to cover a bottom surface and the vertical sidewalls of theplurality of first vertical openings over the gate dielectric 538. Theconductive material, 540-1, 540-2, . . . , 540-4, may be conformallydeposited to a particular thickness (t2) to form vertically orientedaccess lines, such as shown as access lines 103-1, 103-2, . . . , 103-Q(which also may be referred to a word lines) shown in FIG. 1, et. seq.,and as suited to a particular design rule. For example, the conductivematerial, 540-1, 540-2, . . . , 540-4, may be conformally deposited to athickness of approximately 20 nanometers (nm). Embodiments, however, arenot limited to this example. By way of example, and not by way oflimitation, the conductive material, 540-1, 540-2, . . . , 540-4, may becomprise a metal such as tungsten (W), metal composition, titaniumnitride (TiN), doped amorphous silicon, and/or some other combinationthereof as also described in FIG. 3.

As shown in FIG. 5B, the conductive material, 540-1, 540-2, . . . ,540-4, may be recessed back to remain only along the vertical sidewallsof the elongated vertical, pillar columns, now shown as 542-1, 542-2,and 542-3 in the cross-sectional view of FIG. 5B. The plurality ofseparate, vertical access lines formed from the conductive material,540-1, 540-2, . . . , 540-4, may be recessed back by using a suitableselective, anisotropic etch process to remove the conductive material,540-1, 540-2, . . . , 540-4, from a bottom surface of the first verticalopenings, e.g., 500 in FIG. 5A, exposing the gate dielectric 538 on thebottom surface to form separate, vertical access lines, 540-1, 540-2, .. . , 540-4. As shown in FIG. 5B, a dielectric material 539, such as anoxide or other suitable spin on dielectric (SOD), may then be depositedin the first vertical openings 500, using a process such as CVD, to fillthe first vertical openings 500. The dielectric may be planarized to atop surface of the hard mask 535 of the vertical semiconductor stack,using chemical mechanical planarization (CMP) or other suitablesemiconductor fabrication technique. A subsequent photolithographicmaterial 536, e.g., hard mask, may be deposited using CVD and planarizedusing CMP to cover and close the first vertical openings 500 over theseparate, vertical access lines, 540-1, 540-2, . . . , 540-4. Similarsemiconductor process techniques may be used at other points of thesemiconductor fabrication process described herein.

FIG. 6A illustrates an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure. FIG. 6A illustrates a top down view of a semiconductorstructure, at a particular point in time, in a semiconductor fabricationprocess, according to one or more embodiments. In the example embodimentof FIG. 6A, the method comprises using a photolithographic process topattern the photolithographic mask 636, 536 in FIG. 5B. The method inFIG. 6A, further illustrates using a selective, isotropic etchantprocess to remove portions of the exposed conductive material, 640-1,640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1), and 640-Z, toseparate and individually form the plurality of separate, verticalaccess lines, 640-1, 640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1),and 640-Z, e.g., access lines 103-1, 103-2, . . . , 103-Q in FIG. 1, et.seq. Hence the plurality of separate, vertical access lines, 640-1,640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1), and 640-Z, are shownalong the sidewalls of the elongated vertical, pillar columns, e.g.,along sidewalls of the elongated vertical, pillar columns 542-1, 542-2,and 542-3 in the cross-sectional view of FIG. 5B.

As shown in the example of FIG. 6A, the exposed conductive material,640-1, 640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1), and 640-Z,may be removed back to the gate dielectric material 638, in the firstvertical openings, e.g., 500 in FIG. 5A, using a suitable selective,isotropic etch process. As shown in FIG. 6A, a subsequent dielectricmaterial 641, such as an oxide or other suitable spin on dielectric(SOD), may then be deposited to fill the remaining openings from wherethe exposed conductive material, 640-1, 640-2, . . . , 640-N, 640-(N+1),. . . , 640-(Z−1), and 640-Z, was removed using a process such as CVD,or other suitable technique. The dielectric material 641 may beplanarized to a top surface of the previous hard mask 635 of thevertical semiconductor stack, e.g., 401 as shown in FIG. 4, using aprocess such as CMP, or other suitable technique. In some embodiments, asubsequent photolithographic material 637, e.g., hard mask, may bedeposited using CVD and planarized using CMP to cover and close theplurality of separate, vertical access lines, 640-1, 640-2, . . . ,640-N, 640-(N+1), . . . , 640-(Z−1), and 640-Z, over a working surfaceof the vertical semiconductor stack, 401 in FIG. 4, leaving theplurality of separate, vertical access lines, 640-1, 640-2, . . . ,640-N, 640-(N+1), . . . , 640-(Z−1), and 640-Z, protected along thesidewalls of the elongated vertical, pillar columns. Embodiments,however, are not limited to these process examples.

FIG. 6B illustrates a cross sectional view, taken along cut-line A-A′ inFIG. 6A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 6B is away from the plurality of separate, vertical access lines,640-1, 640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1), and shows therepeating iterations of alternating layers of a first dielectricmaterial, 630-1, 630-2, . . . , 630-N, a semiconductor material, 632-1,632-2, . . . , 632-N, and a second dielectric material, 633-1, 633-2, .. . , 633-N, on a semiconductor substrate 600 to form the verticalstack, e.g. 401 as shown in FIG. 4. As shown in FIG. 6B, a verticaldirection 611 is illustrated as a third direction (D3), e.g.,z-direction in an x-y-z coordinate system, analogous to the thirddirection (D3) 111, among first, second and third directions, shown inFIGS. 1-3. The plane of the drawing sheet, extending right and left, isin a first direction (D1) 609. In the example embodiment of FIG. 6B, thedielectric material 641 is shown filling the vertical openings on theresidual gate dielectric 638 deposition. The hard mask 637, describedabove, caps the illustrated structure.

FIG. 6C illustrates a cross sectional view, taken along cut-line B-B′ inFIG. 6A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 6C is illustrated extending in the second direction (D2) 605 alongan axis of the repeating iterations of alternating layers of a firstdielectric material, 630-1, 630-2, . . . , 630-N, a semiconductormaterial, 632-1, 632-2, . . . , 632-N, and a second dielectric material,633-1, 633-2, . . . , 633-N, along and in which the horizontallyoriented access devices and horizontally oriented storage nodes, e.g.,capacitor cells, can be formed within the layers of semiconductormaterial, 632-1, 632-2, . . . , 632-N. In FIG. 6C, a neighboring,opposing vertical access line 640-3 is illustrated by a dashed lineindicating a location set in from the plane and orientation of thedrawing sheet.

FIG. 6D illustrates a cross sectional view, taken along cut-line C-C′ inFIG. 6A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 6D is illustrated extending in the second direction (D2) 605 alongan axis of the repeating iterations of alternating layers of a firstdielectric material, 630-1, 630-2, . . . , 630-N, a semiconductormaterial, 632-1, 632-2, . . . , 632-N, and a second dielectric material,633-1, 633-2, . . . , 633-N, outside of a region in which thehorizontally oriented access devices and horizontally oriented storagenodes, e.g., capacitor cells, will be formed within the layers ofsemiconductor material, 632-1, 632-2, . . . , 632-N. In FIG. 6C, thedielectric material 641 is shown filling the space between thehorizontally oriented access devices and horizontally oriented storagenodes, which can be spaced along a first direction (D1) 611, extendinginto and out from the plane of the drawings sheet, for a threedimensional array of vertically oriented memory cells. At the left endof the drawing sheet is shown the repeating iterations of alternatinglayers of a first dielectric material, 630-1, 630-2, . . . , 630-N, asemiconductor material, 632-1, 632-2, . . . , 632-N, and a seconddielectric material, 633-1, 633-2, . . . , 633-N, at which location ahorizontally oriented digit line, e.g., digit lines 107-1, 107-2, . . ., 107-P shown in FIG. 1, et. seq., can be integrated to form electricalcontact with the second source/drain regions or digit line conductivecontact material, described in more detail below.

FIG. 6E illustrates a cross sectional view, taken along cut-line D-D′ inFIG. 6A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 6E is illustrated, right to left in the plane of the drawing sheet,extending in the first direction (D1) 609 along an axis of the repeatingiterations of alternating layers of a first dielectric material, 630-1,630-2, . . . , 630-N, a semiconductor material, 632-1, 632-2, . . . ,632-N, and a second dielectric material, 633-1, 633-2, . . . , 633-N,intersecting across the plurality of separate, vertical access lines,640-1, 640-2, . . . , 640-N, 640-(N+1), . . . , 640-(Z−1), andintersecting regions of the semiconductor material, 632-1, 632-2, . . ., 632-N, in which a channel and body region may be formed, separatedfrom the plurality of separate, vertical access lines, 640-1, 640-2, . .. , 640-N, 640-(N+1), . . . , 640-(Z−1), by the gate dielectric 638. InFIG. 6E, the first dielectric fill material 639 is shown separating thespace between neighboring horizontally oriented access devices andhorizontally oriented storage nodes, which may be formed extending intoand out from the plane of the drawing sheet as described in more detailbelow, and can be spaced along a first direction (D1) 609 and stackedvertically in arrays extending in the third direction (D3) 611 in thethree dimensional (3D) memory.

FIG. 7A illustrates an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure. FIG. 7A illustrates a top down view of a semiconductorstructure, at a particular point in time, in a semiconductor fabricationprocess, according to one or more embodiments. In the example embodimentof FIG. 7A, the method comprises using a photolithographic process topattern the photolithographic masks 735, 736 and/or 737, e.g., 635, 636,and/or 637 in FIGS. 6A-6E. The method in FIG. 7A, further illustratesusing one or more etchant processes to form a vertical opening 751-1,751-N, 751-(N+1), and 751-Z (individually or collectively referred to asvertical opening 751) in a storage node region 750 (and 744 in FIGS. 7Aand 7C) through the vertical stack and extending predominantly in thefirst horizontal direction (D1) 709. The one or more etchant processesforms a vertical opening 751 to expose third sidewalls in the repeatingiterations of alternating layers of a first dielectric material, 730-1,730-2, . . . , 730-N, a semiconductor material, 732-1, 732-2, . . . ,732-N, and a second dielectric material, 733-1, 733-2, . . . , 733-N, inthe vertical stack, shown in FIGS. 7B-7E, adjacent a second region ofthe semiconductor material. Other numerated components may be analogousto those shown and discussed in connection with FIG. 6A-6E.

In some embodiments, this process is performed before selectivelyremoving an access device region, e.g., transistor region, of thesemiconductor material in which to form a first source/drain region,channel region, and second source/drain region of the horizontallyoriented access devices. In other embodiments, this process is performedafter selectively removing an access device region of the semiconductormaterial in which to form a first source/drain region, channel region,and second source/drain region of the horizontally oriented accessdevices.

According to an example embodiment, shown in FIGS. 7B-7E, the methodcomprises forming a second vertical opening 751 in the vertical stack(401 in FIG. 4A) and selectively etching the second region 744 of thesemiconductor material, 732-1, 732-2, . . . , 732-N, to form a secondhorizontal opening 734 a second horizontal distance (D2 opening) backfrom the vertical opening 751 in the vertical stack (401 in FIG. 4A).According to embodiments, selectively etching the second region 744 ofthe semiconductor material, 732-1, 732-2, . . . , 732-N can compriseusing an atomic layer etching (ALE) process. As will be explained morein connection with FIG. 7C, a second source/drain region 778 can beformed in the semiconductor material, 732-1, 732-2, . . . , 732-N at adistal end of the second horizontal openings 734 from the verticalopening.

FIG. 7B illustrates a cross sectional view, taken along cut-line A-A′ inFIG. 7A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 7B is away from the plurality of separate, vertical access lines,740-1, 740-2, . . . , 740-N, 740-(N+1), . . . , 740-(Z−1), and showsrepeating iterations of alternating layers of a dielectric material,730-1, 730-2, . . . , 730-(N+1), a semiconductor material, 732-1, 732-2,. . . , 732-N, and a second dielectric material, 733-1, 733-2, . . . ,733-N separated by an opening 751, on a semiconductor substrate 700 toform the vertical stack. As shown in FIG. 7B, a vertical direction 711is illustrated as a third direction (D3), e.g., z-direction in an x-y-zcoordinate system, analogous to the third direction (D3) 111, amongfirst, second and third directions, shown in FIGS. 1-3. The plane of thedrawing sheet, extending right and left, is in a first direction (D1)709. In the example embodiment of FIG. 7B, the materials within thevertical stack—a dielectric material, 730-1, 730-2, . . . , 730-(N+1), asemiconductor material, 732-1, 732-2, . . . , 732-N, and a seconddielectric material, 733-1, 733-2, . . . , 733-N extending into and outof the plane of the drawing sheet in second direction (D2) and along anaxis of orientation of the horizontal access devices and horizontalstorage nodes of the arrays of vertically stacked memory cells of thethree dimensional (3D) memory.

FIG. 7C illustrates a cross sectional view, taken along cut-line B-B′ inFIG. 7A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 7C is illustrated extending in the second direction (D2) 705, leftand right along the plane of the drawing sheet, along an axis of therepeating iterations of alternating layers of a first dielectricmaterial, 730-1, 730-2, . . . , 730-N, a semiconductor material, 732-1,732-2, . . . , 732-N, and a second dielectric material, 733-1, 733-2, .. . , 733-N, and in which the horizontally oriented access devices andhorizontally oriented storage nodes, e.g., capacitor cells, can beformed within the layers of semiconductor material, 732-1, 732-2, . . ., 732-N. In the example embodiment of FIG. 7C, an opening 756 isillustrated where the horizontally oriented storage nodes, e.g.,capacitor cells, may be formed later in this semiconductor fabricationprocess.

In the example embodiment of FIG. 7C, a vertical opening 751 andhorizontal openings 734 are shown formed from the mask, patterning andetching process described in connection with FIG. 7A. As shown in FIG.7C, the semiconductor material, 732-1, 732-2, . . . , 732-N, in thesecond region 744 has been selectively removed to form the horizontalopenings 734. In one example, an atomic layer etching (ALE) process isused to selectively etch the semiconductor material, 732-1, 732-2, . . ., 732-N, and remove a second distance (D2 opening) back from thevertical opening 751. Horizontally oriented storage nodes, e.g.,capacitor cells, may be formed, as shown in FIGS. 8A-8E, later or first,relative to the fabrication process shown in FIGS. 4A-4K, in the secondhorizontal openings 734.

According to one example embodiment, as shown in FIG. 7C a secondsource/drain region 778 may be formed by flowing a high energy gas phasedopant, such as Phosphorous (P) for an n-type transistor, into thesecond horizontal openings 734 to implant the dopant in thesemiconductor material, 732-1, 732-2, . . . , 732-N, at a distal end ofthe second horizontal openings 734 from the vertical opening 751. In oneexample, gas phase doping may be used to achieve a highly isotropice.g., non-directional doping, to form the second source/drain region 778to a horizontally oriented access device in region 742. In anotherexample, thermal annealing with doping gas, such as phosphorous may beused with a high energy plasma assist to break the bonding. Embodiments,however, are not so limited and other suitable semiconductor fabricationtechniques may be utilized.

As shown further in FIG. 8C, a first electrode, e.g., 861, forhorizontally oriented storage nodes are to be coupled to the secondsource/drain regions 778 of the horizontal access devices. As shownlater in FIG. 8C, such horizontally oriented storage nodes are shownformed in a second horizontal opening 734 extending in second direction(D2), left and right in the plane of the drawing sheet, a seconddistance (D2 opening) from the vertical opening 751 formed in thevertical stack, e.g., 401 in FIG. 4A, and along an axis of orientationof the horizontal access devices and horizontal storage nodes of thearrays of vertically stacked memory cells of the three dimensional (3D)memory. In FIG. 7C, a neighboring, opposing vertical access line 740-3is illustrated by a dashed line indicating a location set inward fromthe plane and orientation of the drawing sheet.

FIG. 7D illustrates a cross sectional view, taken along cut-line C-C′ inFIG. 7A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 7D is illustrated extending in the second direction (D2) 705, leftand right in the plane of the drawing sheet, along an axis of therepeating iterations of alternating layers of a first dielectricmaterial, 730-1, 730-2, . . . , 730-N, a semiconductor material, 732-1,732-2, . . . , 732-N, and a second dielectric material, 733-1, 733-2, .. . , 733-N, outside of a region in which the horizontally orientedaccess devices and horizontally oriented storage nodes, e.g., capacitorcells, will be formed within the layers of semiconductor material,732-1, 732-2, . . . , 732-N. At the left end of the drawing sheet isshown the repeating iterations of alternating layers of a firstdielectric material, 730-1, 730-2, . . . , 730-N, a semiconductormaterial, 732-1, 732-2, . . . , 732-N, and a second dielectric material,733-1, 733-2, . . . , 733-N, at which location a horizontally orienteddigit line, e.g., digit lines 107-1, 107-2, . . . , 107-P shown in FIG.1, et. seq., can be integrated to form electrical contact with firstsource/drain regions or digit line conductive contact material,described above in connection with FIGS. 4A-4K.

Again, while first and second source/drain region references are usedherein to denote two separate and distinct source/drain regions, it isnot intended that the source/drain region referred to as the “first”and/or “second” source/drain regions have some unique meaning. It isintended only that one of the source/drain regions is connected to adigit line, e.g., 107-2, and the other may be connected to a storagenode.

FIG. 7E illustrates a cross sectional view, taken along cut-line D-D′ inFIG. 7A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 7E is illustrated, right to left in the plane of the drawing sheet,extending in the first direction (D1) 709 along an axis of the repeatingiterations of alternating layers of a first dielectric material, 730-1,730-2, . . . , 730-N, a semiconductor material, 732-1, 732-2, . . . ,732-N, and a second dielectric material, 733-1, 733-2, . . . , 733-N,intersecting across the plurality of separate, vertical access lines,740-1, 740-2, . . . , 740-4, and intersecting regions of thesemiconductor material, 732-1, 732-2, . . . , 732-N, in which a channeland body region may be formed, separated from the plurality of separate,vertical access lines, 740-1, 740-2, . . . , 740-4, by the gatedielectric 738. In FIG. 7E, the first dielectric fill material 739 isshown separating the space between neighboring horizontally orientedaccess devices which may be formed extending into and out from the planeof the drawing sheet as described in connection with FIGS. 4A-4K, andcan be spaced along a first direction (D1) 709 and stacked vertically inarrays extending in the third direction (D3) 711 in the threedimensional (3D) memory.

FIG. 8A illustrates an example method, at another stage of asemiconductor fabrication process, for forming arrays of verticallystacked memory cells having a channel and body region for semiconductordevices, in accordance with a number of embodiments of the presentdisclosure. FIG. 8A illustrates a top down view of a semiconductorstructure, at a particular point in time, in a semiconductor fabricationprocess, according to one or more embodiments. In the example embodimentof FIG. 8A, the method comprises using a photolithographic process topattern the photolithographic masks 835, 836 and/or 837, e.g., 635, 636,and/or 637 in FIGS. 6A-6E or 735, 736, and/or 737 in FIGS. 7A-7E. Themethod in FIG. 8A, further illustrates using one or more etchantprocesses to form a vertical opening 851 in a storage node region 850(and 844 in FIGS. 8A and 8C) through the vertical stack and extendingpredominantly in the first horizontal direction (D1) 809. The one ormore etchant processes forms a vertical opening 851 to expose thirdsidewalls in the repeating iterations of alternating layers of a firstdielectric material, 830-1, 830-2, . . . , 830-N, a semiconductormaterial, 832-1, 832-2, . . . , 832-N, and a second dielectric material,833-1, 833-2, . . . , 833-N, in the vertical stack, shown in FIGS.8B-8E, adjacent a second region of the semiconductor material. Othernumerated components may be analogous to those shown and discussed inconnection with FIGS. 6 and 7.

In some embodiments, this process is performed after selectivelyremoving an access device region of the semiconductor material in whichto form a first source/drain region, channel region, and secondsource/drain region of the horizontally oriented access devices, asillustrated in FIG. 7. According to an example embodiment, shown inFIGS. 8B-8E, the method comprises selectively etching the second regionof the semiconductor material, 832-1, 832-2, . . . , 832-N, to deposit asecond source/drain region and capacitor cells through the secondhorizontal opening, which is a second horizontal distance back from avertical opening 851 in the vertical stack. In some embodiments, asshown in FIGS. 8B-8E, the method comprises forming capacitor cell as thestorage node in the second horizontal opening. By way of example, andnot by way of limitation, forming the capacitor comprises using anatomic layer deposition (ALD) process to sequentially deposit, in thesecond horizontal opening, a first electrode 861 and a second electrode856 separated by a cell dielectric 863. Other suitable semiconductorfabrication techniques and/or storage nodes structures may be used.

FIG. 8B illustrates a cross sectional view, taken along cut-line A-A′ inFIG. 8A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 8B is away from the plurality of separate, vertical access lines,840-1, 840-2, . . . , 840-N, 840-(N+1), . . . , 840-(Z−1), and showsrepeating iterations of alternating layers of a dielectric material,830-1, 830-2, . . . , 830-(N+1) and a second dielectric material 833-1,833-2, . . . , 833-N, separated by horizontally oriented capacitor cellshaving first electrodes 861, e.g., bottom cell contact electrodes, celldielectrics 863, and second electrodes 856, e.g., top, common nodeelectrodes, on a semiconductor substrate 800 to form the vertical stack.As shown in FIG. 8B, a vertical direction 811 is illustrated as a thirddirection (D3), e.g., z-direction in an x-y-z coordinate system,analogous to the third direction (D3) 111, among first, second and thirddirections, shown in FIGS. 1-3. The plane of the drawing sheet,extending right and left, is in a first direction (D1) 809. In theexample embodiment of FIG. 8B, the first electrodes 861, e.g., bottomelectrodes to be coupled to source/drain regions of horizontal accessdevices, and second electrodes 856 are illustrated separated by a celldielectric material 863 extending into and out of the plane of thedrawing sheet in second direction (D2) and along an axis of orientationof the horizontal access devices and horizontal storage nodes of thearrays of vertically stacked memory cells of the three dimensional (3D)memory.

FIG. 8C illustrates a cross sectional view, taken along cut-line B-B′ inFIG. 8A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 8C is illustrated extending in the second direction (D2) 805, leftand right along the plane of the drawing sheet, along an axis of therepeating iterations of alternating layers of a first dielectricmaterial, 830-1, 830-2, . . . , 830-N, a semiconductor material, 832-1,832-2, . . . , 832-N, and a second dielectric material, 833-1, 833-2, .. . , 833-N, along and in which the horizontally oriented access devicesand horizontally oriented storage nodes, e.g., capacitor cells, can beformed within the layers of semiconductor material, 832-1, 832-2, . . ., 832-N. In the example embodiment of FIG. 8C, the horizontally orientedstorage nodes, e.g., capacitor cells, are illustrated as having beenformed in this semiconductor fabrication process and first electrodes861, e.g., bottom electrodes to be coupled to source/drain regions ofhorizontal access devices, and second electrodes 856, e.g., topelectrodes to be coupled to a common electrode plane such as a groundplane, separated by cell dielectrics 863, are shown. However,embodiments are not limited to this example. In other embodiments thefirst electrodes 861, e.g., bottom electrodes to be coupled tosource/drain regions of horizontal access devices, and second electrodes856, e.g., top electrodes to be coupled to a common electrode plane suchas a ground plane, separated by cell dielectrics 863, may be formedsubsequent to forming a first source/drain region, a channel and bodyregion, and a second source/drain region in a region of thesemiconductor material, 832-1, 832-2, . . . , 832-N, intended forlocation, e.g., placement formation, of the horizontally oriented accessdevices, described next.

In the example embodiment of FIG. 8C, the horizontally oriented storagenodes having the first electrodes 861, e.g., bottom electrodes to becoupled to source/drain regions of horizontal access devices, and secondelectrodes 856, e.g., top electrodes to be coupled to a common electrodeplane such as a ground plane, are shown formed in a second horizontalopening, e.g., 734 shown in FIG. 7C, extending in second direction (D2),left and right in the plane of the drawing sheet, a second distance (D2opening) from the vertical opening, e.g., 751 in FIG. 7C, formed in thevertical stack, e.g., 401 in FIG. 4A, and along an axis of orientationof the horizontal access devices and horizontal storage nodes of thearrays of vertically stacked memory cells of the three dimensional (3D)memory. In FIG. 8C, a neighboring, opposing vertical access line 840-3is illustrated by a dashed line indicating a location set inward fromthe plane and orientation of the drawing sheet.

FIG. 8D illustrates a cross sectional view, taken along cut-line C-C′ inFIG. 8A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 8D is illustrated extending in the second direction (D2) 805, leftand right in the plane of the drawing sheet, along an axis of therepeating iterations of alternating layers of a first dielectricmaterial, 830-1, 830-2, . . . , 830-N, a semiconductor material, 832-1,832-2, . . . , 832-N, and a second dielectric material, 833-1, 833-2, .. . , 833-N, outside of a region in which the horizontally orientedaccess devices and horizontally oriented storage nodes, e.g., capacitorcells, will be formed within the layers of semiconductor material,832-1, 832-2, . . . , 832-N. In FIG. 8C, the dielectric material 841 isshown filling the space between the horizontally oriented accessdevices, which can be spaced along a first direction (D1), extendinginto and out from the plane of the drawings sheet, for a threedimensional array of vertically oriented memory cells. However, in thecross sectional view of FIG. 8D, the second electrode 856, e.g., top,common electrode to the capacitor cell structure, is additionally shownpresent in the space between horizontally neighboring devices. At theleft end of the drawing sheet is shown the repeating iterations ofalternating layers of a first dielectric material, 830-1, 830-2, . . . ,830-N, a semiconductor material, 832-1, 832-2, . . . , 832-N, and asecond dielectric material, 833-1, 833-2, . . . , 833-N, at whichlocation a horizontally oriented digit line, e.g., digit lines 107-1,107-2, . . . , 107-P shown in FIG. 1, et. seq., can be integrated toform electrical contact with the second source/drain regions or digitline conductive contact material, described in more detail below.

FIG. 8E illustrates a cross sectional view, taken along cut-line D-D′ inFIG. 8A, showing another view of the semiconductor structure at thisparticular point in one example semiconductor fabrication process of anembodiment of the present disclosure. The cross sectional view shown inFIG. 8E is illustrated, right to left in the plane of the drawing sheet,extending in the first direction (D1) 809 along an axis of the repeatingiterations of alternating layers of a first dielectric material, 830-1,830-2, . . . , 830-N, a semiconductor material, 832-1, 832-2, . . . ,832-N, and a second dielectric material, 833-1, 833-2, . . . , 833-N,intersecting across the plurality of separate, vertical access lines,840-1, 840-2, . . . , 840-4, and intersecting regions of thesemiconductor material, 832-1, 832-2, . . . , 832-N, in which a channeland body region may be formed, separated from the plurality of separate,vertical access lines, 840-1, 840-2, . . . , 840-4, by the gatedielectric 838. In FIG. 8E, the first dielectric fill material 839 isshown separating the space between neighboring horizontally orientedaccess devices and horizontally oriented storage nodes, which may beformed extending into and out from the plane of the drawing sheet asdescribed in more detail below, and can be spaced along a firstdirection (D1) 809 and stacked vertically in arrays extending in thethird direction (D3) 811 in the three dimensional (3D) memory. FIG. 8illustrates a cross-sectional view of a portion of an examplehorizontally oriented access device coupled to a horizontally orientedstorage node and coupled to vertically oriented access lines andhorizontally oriented digit lines, as may form part of an array ofvertically stacked memory cells, in accordance with a number ofembodiments of the present disclosure. The horizontally oriented accessdevice 801 can have a first source/drain region and a second sourcedrain region separated by a channel and body region, and gates opposingthe channel region and separated therefrom by a gate dielectric.

FIG. 9 is a block diagram of an apparatus in the form of a computingsystem 900 including a memory device 903 in accordance with a number ofembodiments of the present disclosure. As used herein, a memory device903, a memory array 910, and/or a host 902, for example, might also beseparately considered an “apparatus.” According to embodiments, thememory device 903 may comprise at least one memory array 910 with amemory cell formed having a digit line and body contact, according tothe embodiments described herein.

In this example, system 900 includes a host 902 coupled to memory device903 via an interface 904. The computing system 900 can be a personallaptop computer, a desktop computer, a digital camera, a mobiletelephone, a memory card reader, or an Internet-of-Things (IoT) enableddevice, among various other types of systems. Host 902 can include anumber of processing resources (e.g., one or more processors,microprocessors, or some other type of controlling circuitry) capable ofaccessing memory 903. The system 900 can include separate integratedcircuits, or both the host 902 and the memory device 903 can be on thesame integrated circuit. For example, the host 902 may be a systemcontroller of a memory system comprising multiple memory devices 903,with the system controller 905 providing access to the respective memorydevices 903 by another processing resource such as a central processingunit (CPU).

In the example shown in FIG. 1, the host 902 is responsible forexecuting an operating system (OS) and/or various applications (e.g.,processes) that can be loaded thereto (e.g., from memory device 903 viacontroller 905). The OS and/or various applications can be loaded fromthe memory device 903 by providing access commands from the host 902 tothe memory device 903 to access the data comprising the OS and/or thevarious applications. The host 902 can also access data utilized by theOS and/or various applications by providing access commands to thememory device 903 to retrieve said data utilized in the execution of theOS and/or the various applications.

For clarity, the system 900 has been simplified to focus on featureswith particular relevance to the present disclosure. The memory array910 can be a DRAM array comprising at least one memory cell having adigit line and body contact formed according to the techniques describedherein. For example, the memory array 910 can be an unshielded DL 4F2array such as a 3D-DRAM memory array. The array 910 can comprise memorycells arranged in rows coupled by word lines (which may be referred toherein as access lines or select lines) and columns coupled by digitlines (which may be referred to herein as sense lines or data lines).Although a single array 910 is shown in FIG. 1, embodiments are not solimited. For instance, memory device 903 may include a number of arrays910 (e.g., a number of banks of DRAM cells).

The memory device 903 includes address circuitry 906 to latch addresssignals provided over an interface 904. The interface can include, forexample, a physical interface employing a suitable protocol (e.g., adata bus, an address bus, and a command bus, or a combineddata/address/command bus). Such protocol may be custom or proprietary,or the interface 904 may employ a standardized protocol, such asPeripheral Component Interconnect Express (PCIe), Gen-Z, CCIX, or thelike. Address signals are received and decoded by a row decoder 908 anda column decoder 912 to access the memory array 910. Data can be readfrom memory array 910 by sensing voltage and/or current changes on thesense lines using sensing circuitry 911. The sensing circuitry 911 cancomprise, for example, sense amplifiers that can read and latch a page(e.g., row) of data from the memory array 910. The I/O circuitry 907 canbe used for bi-directional data communication with the host 902 over theinterface 904. The read/write circuitry 913 is used to write data to thememory array 910 or read data from the memory array 910. As an example,the circuitry 913 can comprise various drivers, latch circuitry, etc.

Control circuitry 905 includes registers 918 and decodes signalsprovided by the host 902. The signals can be commands provided by thehost 902. These signals can include chip enable signals, write enablesignals, and address latch signals that are used to control operationsperformed on the memory array 910, including data read operations, datawrite operations, and data erase operations. In various embodiments, thecontrol circuitry 905 is responsible for executing instructions from thehost 902. The control circuitry 905 can comprise a state machine, asequencer, and/or some other type of control circuitry, which may beimplemented in the form of hardware, firmware, or software, or anycombination of the three. In some examples, the host 902 can be acontroller external to the memory device 103. For example, the host 902can be a memory controller which is coupled to a processing resource ofa computing device.

The term semiconductor can refer to, for example, a material, a wafer,or a substrate, and includes any base semiconductor structure.“Semiconductor” is to be understood as including silicon-on-sapphire(SOS) technology, silicon-on-insulator (SOI) technology,thin-film-transistor (TFT) technology, doped and undoped semiconductors,epitaxial silicon supported by a base semiconductor structure, as wellas other semiconductor structures. Furthermore, when reference is madeto a semiconductor in the preceding description, previous process stepsmay have been utilized to form regions/junctions in the basesemiconductor structure, and the term semiconductor can include theunderlying materials containing such regions/junctions.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar (e.g., the same) elements or components between differentfigures may be identified by the use of similar digits. As will beappreciated, elements shown in the various embodiments herein can beadded, exchanged, and/or eliminated so as to provide a number ofadditional embodiments of the present disclosure. In addition, as willbe appreciated, the proportion and the relative scale of the elementsprovided in the figures are intended to illustrate the embodiments ofthe present disclosure and should not be taken in a limiting sense.

As used herein, “a number of” or a “quantity of” something can refer toone or more of such things. For example, a number of or a quantity ofmemory cells can refer to one or more memory cells. A “plurality” ofsomething intends two or more. As used herein, multiple acts beingperformed concurrently refers to acts overlapping, at least in part,over a particular time period. As used herein, the term “coupled” mayinclude electrically coupled, directly coupled, and/or directlyconnected with no intervening elements (e.g., by direct physicalcontact), indirectly coupled and/or connected with intervening elements,or wirelessly coupled. The term coupled may further include two or moreelements that co-operate or interact with each other (e.g., as in acause and effect relationship). An element coupled between two elementscan be between the two elements and coupled to each of the two elements.

It should be recognized the term vertical accounts for variations from“exactly” vertical due to routine manufacturing, measuring, and/orassembly variations and that one of ordinary skill in the art would knowwhat is meant by the term “perpendicular.” For example, the vertical cancorrespond to the z-direction. As used herein, when a particular elementis “adjacent to” another element, the particular element can cover theother element, can be over the other element or lateral to the otherelement and/or can be in direct physical contact the other element.Lateral to may refer to the horizontal direction (e.g., the y-directionor the x-direction) that may be perpendicular to the z-direction, forexample.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anarrangement calculated to achieve the same results can be substitutedfor the specific embodiments shown. This disclosure is intended to coveradaptations or variations of various embodiments of the presentdisclosure. It is to be understood that the above description has beenmade in an illustrative fashion, and not a restrictive one. Combinationof the above embodiments, and other embodiments not specificallydescribed herein will be apparent to those of skill in the art uponreviewing the above description. The scope of the various embodiments ofthe present disclosure includes other applications in which the abovestructures and methods are used. Therefore, the scope of variousembodiments of the present disclosure should be determined withreference to the appended claims, along with the full range ofequivalents to which such claims are entitled.

What is claimed is:
 1. A method, comprising: forming layers of a firstdielectric material, a semiconductor material, and a second dielectricmaterial, in repeating iterations vertically to form a vertical stack;forming a vertical opening using an etchant process to expose verticalsidewalls in the vertical stack; depositing a seed material on thevertical sidewall in the vertical stack; and processing the verticalstack under temperature and time parameters such that the seed materialon the sidewall of the semiconductor material advances into thesemiconductor material by a first distance to transform a portion of thesemiconductor material of the first distance into a crystallinestructure.
 2. The method of claim 1, wherein forming layers of the firstdielectric material, the semiconductor material, and the seconddielectric material, in repeating iterations vertically to form thevertical stack, comprises: depositing an oxide material as the firstdielectric material; depositing an amorphous silicon material as thesemiconductor material; and depositing a nitride material as the seconddielectric material.
 3. The method of claim 2, wherein the seed materialcomprises Nickel as the seed material and processing the vertical stackunder the temperature and time parameters comprises forming a Nickel(Ni) silicide with the Nickel and the amorphous silicon at the firstdistance away from the vertical opening.
 4. The method of claim 2,wherein the seed material comprises Cobalt as the seed material andprocessing the vertical stack under the temperature and time parameterscomprises forming a Cobalt (Co) silicide with the Cobalt and theamorphous silicon at the first distance away from the vertical opening.5. The method of claim 2, wherein the seed material comprises Silver asthe seed material and processing the vertical stack under thetemperature and time parameters comprises forming a Silver (Ag) silicidewith the Silver and the amorphous silicon at the first distance awayfrom the vertical opening.
 6. The method of claim 1, further comprisingforming the vertical opening to have a width in a range of 50-500nanometers (nm) and a depth in a range of 500-20,000 nm.
 7. The methodof claim 1, further comprising depositing the seed material to athickness in a range of approximately 5-50 angstroms (Å).
 8. The methodof claim 1, further comprising advancing the seed material within thesemiconductor material to a horizontal distance (D1) of approximately200 nanometers (nm) from the vertical opening.
 9. The method of claim 1,further comprising processing the vertical stack under temperature andtime parameters such that, as the seed material advances horizontallywithin the semiconductor material, it transforms the crystallinestructure of the portion of the semiconductor material according to ametal induced lateral crystallization (MILC) process.
 10. The method ofclaim 1, further comprising processing the vertical stack undertemperature and time parameters such that as the seed material advanceshorizontally within the semiconductor material it transforms thecrystalline structure of the portion of the semiconductor materialaccording to a solid phase crystallization (SPC).
 11. The method ofclaim 1, further comprising processing the vertical stack undertemperature and time parameters such that, as the seed material advanceswithin the semiconductor material, it transforms the crystallinestructure of the portion of the semiconductor material into amonocrystalline silicon material.
 12. The method of claim 1, furthercomprising processing the vertical stack under temperature and timeparameters such that, as the seed material advances within thesemiconductor material, it transforms the crystalline structure of theportion of the semiconductor material to increase a size of individualcrystals in the portion of the semiconductor material.
 13. A method,comprising: depositing layers of an oxide material, a silicon material,and a nitride material, in repeating iterations vertically to form avertical stack; forming a vertical opening using an etchant process toexpose vertical sidewalls in the vertical stack; selectively depositinga metal seed material to form a metal silicide on vertical sidewalls ofthe silicon material in the vertical opening of the vertical stack; andprocessing the vertical stack under temperature and time parameters suchthat the metal silicide advances horizontally through the siliconmaterial, bounded by the oxide material and the nitride material, andtransforms a portion of the silicon material from an amorphous siliconstructure to a monocrystalline silicon structure along a length of afirst distance from the vertical opening.
 14. The method of claim 13,further comprising processing the vertical stack such that the metalsilicide advances horizontally through the silicon material the firstdistance and provides a dividing interface between the monocrystallinesilicon and the amorphous silicon structure, wherein crystal on themonocrystalline side of the interface are larger than the crystals inthe amorphous silicon structure.
 15. The method of claim 13, furthercomprising processing the vertical stack at a temperature in a range of400 to 600 degrees Celsius (° C.) such that the metal silicide advanceshorizontally through the silicon material.
 16. The method of claim 13,further comprising processing the vertical stack under temperature andtime parameters such that the metal silicide advances horizontallythrough the silicon material a first distance of at least 200 nanometers(nm).
 17. The method of claim 13, further comprising selectivelydepositing Nickel (Ni) as the metal seed to form a Nickel silicide withthe silicon material.
 18. The method of claim 13, further comprisingselectively depositing the Nickel on the silicon material using anatomic layer deposition (ALD) process.
 19. A method, comprising:depositing layers of an oxide material, an amorphous silicon material,and a nitride material, in repeating iterations vertically to from avertical stack; forming a vertical opening using an etchant process toexpose vertical sidewalls in the vertical stack; selectively depositinga metal seed material on the vertical sidewalls of the amorphous siliconto form a metal silicide using an atomic layer deposition (ALD) process;and processing the vertical stack under temperature and time parametersto horizontally advance the metal silicide through the amorphoussilicon, recrystallizing the amorphous silicon into a monocrystallinesilicon structure a first distance (D1) from the vertical opening todefine a first region in the vertical stack.
 20. The method of claim 19,further comprising: using the recrystallized monocrystalline siliconstructure in the first region for formation of a horizontally orientedaccess device in the vertical stack; and using the metal silicide thefirst distance from the vertical opening as a etch stop whileselectively removing the amorphous silicon from a second region of thevertical stack for formation of a storage node.
 21. The method of claim19, further comprising: using an atomic layer deposition (ALD) processto form a horizontal capacitor cell in the selectively removed amorphoussilicon in the second region; and using the metal silicide material asan ohmic contact to a first electrode of the capacitor formed in thesecond region.
 22. The method of claim 19, further comprising processingthe vertical stack under temperature and time parameters to horizontallyadvance the metal silicide, recrystallizing the amorphous silicon into amonocrystalline silicon structure to have sub-grain boundaries.
 23. Amemory cell array, comprising: a plurality of access transistors stackedon one another, each of the access transistors including a firstsource/drain region, a second source/drain region and a channel regiontherebetween which are horizontally arranged, and a body region, whereinthe channel region and the body region are each formed of a singlecrystalline semiconductor material; a metal silicide within each accesstransistor of the plurality of access transistors, wherein the singlecrystalline semiconductor material of each access transistor is on anopposite side of the metal silicide than an amorphous semiconductormaterial of each access transistor; at least one access line elongatingvertically and coupled to each of the channel regions of the pluralityof access transistors with an intervention of a gate dielectric; aplurality of storage capacitors stacked on one another, each of theplurality of storage capacitors lying horizontally and coupled to acorresponding one of the second source/drain regions of the plurality ofaccess transistors; a plurality of digit lines, each of the plurality ofdigit lines coupled to a corresponding one of the first source/drainregions of the plurality of access transistors; and a body contactelongating vertically and coupled to each of the body regions of theplurality of access transistors.
 24. The memory cell array of claim 23,wherein the access transistors have three nodes comprising the firstsource/drain region (1), the second source/drain region (2), and thechannel region (3), having a direct, electrical body contact.
 25. Thememory cell array of claim 23, wherein the storage capacitors comprisecapacitor cells having a first horizontally oriented electrodeelectrically coupled to the first source/drain regions of the accesstransistors and a second electrode separated from the first horizontallyoriented electrode by a cell dielectric.